add 'parameterized selectors' to the map API

[moredip]

As a user of the API I want a way to parameterize my selectors So I don't have to have to mess around with quote escaping

Currently if you want to pass a string inside a selector you have to worry about silly quoting issues. A better approach would be something like SQL parameterization. Here's a sketch of how it could work:

{
  "selector": "view marked:{foo}",
  "selector_params": {
    "foo": "I'm a string with a quote"
  }
}